Fatty acid polyamide



positions.

United States Patent 3,169,980 FATTY AClD POLYAMKDE George J. Benoit, Jr., San Anselmo, Calif, assignor to California Research Corporatiomsan Francisco, Calii., a corporation of Delaware No Drawing. Filed Mar. 31, 1961, Ser. No. 99,722 2 Claims. (Cl. 260-4945) tion of the lubricant composition in the engine and also act v as abrasives which aggravate the wearing of engine parts.

Many detergents presently employed in lubricant compositions are found to contribute a substantial proportion of the deposits in modern engines. This is due to the fact that the detergents are commonly employed as metal salts and such-metal salts form an ash deposit when the lubricant composition is consumed in the engine. 7

Lubricant compositions also contain pour point depressants to modify the flowing properties of the baseoil so as to lower its pour point. The temperature at which a lubricant composition ceases to how or pour is called its pour point and it is important that lubricant compositions be capable of flowing freely through oil lines and between moving engine parts at low temperatures in order to insure proper functioning of the lubricant composition in the engine. a 1

In accordance with the present invention there is proreaction requires from about 2 to 10 hours.

vided a superior new polyamide ashless detergent having from 2 to 6 Ia-lky1ene amine units each, there being from 2 to 4 carbon atoms in each alkylene group, said polyamide containing from 1 to 3 amine groups in addition to amide groups. v v

The polyamides of this invention as described above are unusually effective in depressing the pour point of the base oil of lubricating viscosity. The characteristically mixed ttatty acid groups of the polyamides provide pour points which are surprisingly lower than similar oils containing polyamid-eschar cterized by either of the fatty acid groups alone. a lnaddition to the pourdepressing properties as mentioned above, the polyamide of the invention acts to prevent engine deposits. Sincethere is no metal component substantially freeof ash forming and detergent properties in combination. This eliminates ashless detergent in accordance with the present inven-.

tion are particularly satisfactory for use inZ-cycle gasoline engines. Such engines are becoming increasingly common in recent years and are bound in chain saws, lawn mowers, outboard marine engines and small cars or motor scooters.

7 Patented Feb. 16, 1955 ice] The polyamides of the present invention may be conveniently illustrated by the following structural fiormula:

in which the alkylene group R contains from 2 to 4 carbon atoms, the radical R is hydrogen or an acyl group 0 Bath which is derived from a mixture of from about 5 to about 30 mole percent of straight-chain fatty acid and from about 70to about mole percent of branched-chain fatty acid, said fatty acids containing from about 12 toabout 30 carbon atoms and n is an integer of from 1 to 5. In

- the above acyl groupR is the aliphatic hydrocarbon residue of thefatty acids. and therefore contains from about 11 to about 29 carbon atoms, there being more than one of siaid acyl groups in the over-all structural formula for the polyamides of the invention.

The polya-mide of this invention is conveniently prepared according to known methods by reacting the polyamine and the mixed fatty acids at conventional temperatures for the usual period oftime required'to amidify the amino groups of the polyalkylene polyamine. For present purposes temperatures in the range from about 250 F. to about 500 are suitable. Usually the amidificatio-n Means for removing water of condensation is employed and reduced pressures are desirable to effect amidification at the lower reaction temperatures.

The proportions of fatty acids mixture and polyalkylene poly-amine may be such that the moles of the fatty acids are equal to the molar equivalents of amine groups in the polyalkylene polyamine. As already mentioned it is preferred that moles of fatty acid be on the average of from about 1 to about 3 moles less than-the number of available amino groups in the polyamine.

The polyamide of the present invention which is formed by the reaction of fatty acid and polyalkylene polyamine is illustrated in the above structural formula as being in the nature of linearpolyamide. Such linear polyamides undergo further condensation upon continued heating at higher temperatures with terminalamino groups to give either the monoor bis-imidazoline ring structure as i1.- lustrated by the following formula: I

Suitable fatty acids for the preparation of the polyamides of thepresent invention contain from 12 to- 30carbon carbon atoms.

acid, etc.

Suitable branched-chain fatty acids. are those derived bysynthesis such asoxidation of olefins and polyolefins.- Acids derir'led-from the 0x0 process (oxidation of OX0; aldehyde intermediates from propylene tetramer) are als'olsuitable. Another source is the polymerization of unsaturated acids-followed ,by hydrogenation. For ex-v ample; an unsaturated acidlsuch as linoleic acid is di-- merized in accordance with typical'polymerization techniques. During the reaction part of the acid product is broken down to given unsaturated mono acid by-product havingmethyl chain branching. This product is hydrogenated resulting in a branched-chain saturated fatty acid of 18 carbon atoms. 1

For present purposes it has been found that Emery Acid 3101 R is particularly useful. This is a monocarboxylic acid having an equivalent weight of 310. It is described as a saturated 18 carbon atom fatty acid having methyl chain branching The polyalkylene polyamines of the invention as mentioned above contain from 2 to 6-alkylene amine units with from 2 to 4 carbon atoms in each alkylene group. Illustrative amines include diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, hexaethyleneheptaamine, heptaethyleneoctaamine, tetrapropylenepentaamine, hexabutyleneheptaamine and the like. For present purposes triethylenetetraamine and tetraethylpentaamine are preferred for availability and effectiveness of Example I In this example the polyamide of tetraethylenepentaamine and a 10:90 mixture of straight and branched-chain acids is prepared.

A reaction vessel is charged with a mixture of 3.7 parts by weight of tetraethylenepentaamine and 0.0002 part by weight of silicone foam inhibitor. The mixture is blanketed with nitrogen gas and heated to about 250 F. A mixture of monocarboxylic acids amounting to about 18.2 parts by weight is introduced to the reaction vessel. This mixture consists of 10 mole percent stearic acid and 90 mole percent Emery 3101 R acid. The mole ratio of tetraethylenepentaamine to total acid is about 1 to 3. The reaction mixture is heated to about 300 F. for a period of about 1 hour and Water of reaction is removed. Following this the reaction temperature is raised to about 400 F. at atmospheric pressure for about one hour and then maintained at about 380 F. under a vacuum equivalent to 4 mm. of mercury pressure for a period of about 7 hours.

Example II This example illustrates the preparation of the polyamide of tetraethylenepentaamine and a5 :95 mixture of straight and branched-chain acids.

To a 2 liter, 3 neck flask equipped with stirrer, thermometer, reflux condenser and means of heating there is charged 189 g. of tetraethylenepenta'amine (1.0 mole) and 0.01 g. of silicon foam inhibitor. The charge is heated under nitrogen to about 190 F. A mixture of 42 g. stearic acid (0.15 mole) and 873 g. Emery 3101 R acid (2.85 mole) is then added. The contents of the flask are heated to 380 F. and then put under a vacuum equivalent to about 20 mm. of mercury pressure. The reaction mixture is held under these conditions for about six hours and then cooled. The yield of product is quantitative.

- Example III In this example the polyamide of tetraethylenepentaamine and a 20:80 mixture of straight andbranchedchain acids is prepared.

Inaccordance with the procedure outlined in Example 11 above, 189 g. of tetraethylenepentaamine, 168 g. of stearic acid (20 mole percent of total acid) and 744 g. of Emery 3101 R acid (80 mole percent of total-acid) are reacted. A total of 3.0 moles of acid per mole of tetraethylenepentaamine is used. The yield of the product amounts to about 100% on the basis of the reactants.-.

The polyamide additivesiof the invention as described above are evaluated as pour depressants in lubricating oils in a number of tests. The base oil is asolvent refined waxy SAE 30 mineral lubricating oil having a pour point of +10 F. The results of the tests are set out in the following table. For convenience a typical polyamine, namely, tetraethylenepentaamine is selected and the illustrative acids chosen are stearic acid and Emery 3101 R acid The pour point tests are performed in accordance with ASTM method D-97. The sample is maintained at a temperature of 115 F. or lower for at least 24 hours prior to the test. The sample is then cooled systematically under quiescent conditions and observed at intervals of 5 F. The pour point is the lowest temperature at which the oil flows when the container is tilted.

Stearic acid, mole percent: Pour point of oil, F.

As shown by the test results of the above table the polyamide additive of this invention imparts surprisingly improved pour point characteristics to lubricant compositions compared to similar compositions containing polyamides of conventional types.

It is further evident that the improved pour point characteristics of the polyamides of this invention are due to the particular proportions of straight-chain fatty acid and branched-chain fatty acid and that proportions within the preferred ranges provide pour points which are unpredictably lower than mixtures of other proportions of acids.

The polyamides of this invention are also useful as pour point depressants and detergents in hydrocarbon based fuels of the type employed in internal combustion engines. Many distillates derived from parafiinic type crude stocks have undesirably high pour points as well as deposit-forming characteristics and require additive compounds such as the polyamides of the present invention. Certain refinery charging stocks such as gas oils and the like are characterized by high pour points, particularly fatty acid containing about 18 carbon atoms produced in the dimerization and hydrogenation of linoleic acid, said polyamide containing from 1 to 3 amine groups in addition to amide groups.

2. The polyamide of fatty acids and tetraethylene pentaamine in which the fatty acids are mixtures of about 10 mole percent of stearic acid and about mole percent of methyl branched-chain fatty acid containing about 18 carbon atoms produced in the dimerization andhydrogenation of linoleic acid, said polyamide containing from 1 to 3 amine groups in addition to amide groups.

References Cited in the file of this patent UNITED STATES PATENTS 2,291,396 Lieber July 28, 1942. 2,345,632 Robinson et a1. Apr. 4, 1944 2,425,392 Robinson et a1. Aug. 12, 1947 Niederhauser Oct. 2, 1956 

1. THE POLYAMIDE OF FATTY ACIDS AND TETRAETHYLENE PENTAAMINE IN WHICH THE FATTY ACIDS ARE MIXTURES OF FROM ABOUT 5 TO ABOUT 30 MOLE PERCENT OF STEARIC ACID AND FROM ABOUT 70 TO ABOUT 95 MOLE PERCENT OF METHYL BRANCHED-CHAIN FATTY ACID CONTAINING ABOUT 18 CARBON ATOMS PRODUCED IN THE DIMERIZATION AND HYDROGENATION OF LINOLEIC ACID, SAID POLYAMIDE CONTAINING FROM 1 TO 3 AMINE GROUPS IN ADDITION TO AMIDE GROUPS. 